Patent GB-208767-A (GB)
Title: A power-operated case-shift mechanism for typewriting machines
IPC: B41J11/14
Filed: 1922-09-22
Abstract: 208,767. Brougham, F. J., (Addograph Co.). Sept. 22, 1922. Case, carriage, and platen-shift mechanisms; shift-key actions; driving-mechanism.-In a relay shift-mechanism, the shift-keys control devices for coupling the shiftable member, which may be a carriage, a platen, or a type-lever segment, to a continuously-driven shaft. A shaft 17, Fig. 3, driven continuously by a motor, carries fast and loose friction-members 18, 19, consisting of a coned fibre disc, and a metal disc having a coned slit flange 19<a>, respectively. The edges of the slits scrape and clean the disc 18. A pinion 26 on the disc 19 engages a sector 27 coupled by a link 33 to a rocking-arm 34 which is connected by a spring 45 to an arm 43 on a rockshaft 39. An arm 40 on the rock-shaft is provided with a roller 41 engaging a shift member. As applied to platen-shift mechanism, the shift member consists of a rail 42, Fig. 8, supported on links 67, connecting a platen frame 65 to a carriage 66. The movements of the platen frame are limited by engagement of the platen shaft 84 with adjustable stop-screws 71, 72 carried by stiff springs 73, 75. Lugs 77 on the lower links 67 co-operate with humps 78 on the springs 75 to prevent rebound of the platen frame. The arm 43 is provided with an ear 44 which abuts on the arm 34, and can be bent to adjust the spring 45. The sector 27 is formed with ears 30 for engaging a rubber stop, supported by an ear which can be bent for adjustment. The arm 34 carries a latch 36 adapted to drop in front of a bar 37 to lock the shift rail in raised position. The disc 19 is controlled by a. spring lever 21 which engages a lug 22 on a lever 23 operated by a locking shiftkey lever 25. Non-locking shift-key levers 64 for releasing the shift rail after operating the keylever 25, or for effecting temporary shift, engage a bail 56 formed with a finger 60 normally engaging a shoulder 62 on a hook 52 pivoted on the key-lever 25. The bail carries a pivoted plate 55 having a finger 54 for engaging a shoulder 53 on the hook 52. A spring normally retains the plate 55 in such a position that a finger 81 thereon is in the plane of the latch 36. A spring blade 47 is secured at one end to the bar 37, the free end projecting slightly and having a finger 50 engaging the front of the hook 52. On depressing momentarily the key-lever 25, the disc 19 is coupled, the sector 27 is rocked, and the shift rail is raised, the spring 45 transmitting the movement without shock. The latch 36 moves over the bar 37 and drops on to a shoulder 65 on the plate 55, the plate having been rocked by means of the hook 52. On release of the keylever 25, the spring 45 causes the arm 34 to make a short return-movement, and the end of the latch 36 pushes the spring 47 into contact with the bar 37, which thereupon arrests the latch. The movement of the spring 47 causes the finger 50 to move the shoulder 62 on the hook 52 out of the path of the finger 60, thereby disconnecting the bail 56 from the key-lever 25. Thereupon, on depressing momentarily either of the key-levers 64, the bail 56 causes the plate 35 to rise and release the latch 36, thereby permitting the shift rail and the shift mechanism to return to the normal position. For temporary shift, either of the key-levers 64 is depressed and held, thereby raising the bail 56 and causing the hook 52 to operate the key-lever 25, the shift-rail being thereupon raised in the above-described manner. When the bail rises, the finger 81 of the plate 55 lifts the latch 36, thereby preventing the latch from being caught by the bar 37, and also preventing the spring 47 from being pushed back and releasing the hook 52 from the bail. The disc 18 slips if the shift-keys are held depressed. Specification 25038/13 is referred to.